Vacuum cleaner

Abstract: A vacuum cleaner includes a ventilating quantity controlling valve (28) in a ventilating path to a runner (24) which rotates respondingly to a sucking force, a rotating angle of the ventilating quantity controlling valve is varied its rotation angle following an increase of the sucking force so that an increase of a sucking quantity is suppressed and an increase of a voltage generated by an electric generator (26) is suppressed, the electric generator being rotated by the runner.

Description: The present invention relates to a vacuum cleaner according to the preamble of claim 1. A vacuum cleaner according to the preamble of claim 1 is known from GB-A-2 082 351. A vacuum cleaner, which is well known from the past years, comprises a main body case 1, a suction hose section 2 and a suction nozzle section 3, as is illustrated in Fig. 5. The main body case 1 has a motor 4, a fan 5, a filter 6, a dust bag 7, a motor controlling circuitry 8 and the like within. The suction hose section 2 comprises a hose 9 and an extention pipe 10. An operating section 11 is provided in a central portion of the suction hose section 2. As one species of vacuum cleaner among vacuum cleaners of such kind, there exists a vacuum cleaner having an electric generator which generates a voltage corresponding to a suction quantity for sucking dust, which vacuum cleaner is developed by the inventor and others. The electric generator is housed within the operating section 11, as is illustrated in Fig. 6, for example. In Fig. 6, when the outside air is sucked through a suction opening 13 by a sucking pressure, a turbine runner 14 is rotated by the sucked air so that the electric generator 12 rotates and generates a voltage. The voltage is supplied as power voltage to a dust sensor circuitry section 17 which includes a light emitting device 15, a light receiving device 16, and the like. But sucking vacuum pressure of household vacuum cleaners varies widely such as about from -40 to 3000 mmAq (-0.004 to 0.29 bar). Therefore, rotating speed of the turbine runner 14 varies greatly such as about from 4000 to 70000 r.p.m. (revolutions per minute). Though the electric generator 12 is directly coupled to the turbine runner 14, the electric generator 12 rotates in correspondence to the great variation of the rotating speed so that the generated voltage varies within an extent from several volts to several tens volts. Therefore, the generated voltage is required stabilization because the generated voltage is used as the power voltage of various controlling circuitries such as the dust sensor circuitry section 7 and the like. Though various electric circuitries are employed for stabilizing the voltage, a disadvantage arises in that each eleciric circuitry requires many electronic parts causing waste such as generation of heat and the like. Further, a disadvantage arises in that excessively high rotation is improper for the turbine and the electric generator in view of durability of bearing arrangement. Document DE-A-23 36 758 discloses a flow controlling valve comprising a rotary shaft and a pair of valve plates disposed on opposite sides of the valve shaft. The present invention was made in view of the problems above-mentioned. It is an object of the present invention to stabilize a generated voltage of an electric generator housed in a vacuum cleaner, with simple arrangement and without employing an electric circuitry. This object is achieved by a vacuum cleaner according to claim 1. Further developments of the invention are given in the subclaims. In this specification, the word "runner" is used to express the runner, impeller and the like. As to the vacuum cleaner, when a degree of vacuum caused by the sucking pressure is raised and thereby a sucking quantity of an outside air becomes great, so as to increase a rotating speed of the runner, the passing through quantity controlling valve moves to close the passing path following the increase of the rotating speed so that an increase of the sucking quantity is suppressed. Consequently, the rotating speed of the runner, and the electric generator are also suppressed increase of their rotating speeds. On the contrary, when a degree of vacuum caused by the sucking pressure is lowered and thereby a sucking quantity of an outside air becomes small, so as to decrease a rotating speed of the runner, the passing through quantity controlling valve moves to open the passing path following the decrease of the rotating speed so that decrease of the sucking quantity is suppressed. Consequently, the rotating speed of the runner, and the electric generator are also suppressed decrease of their rotating speed. Therefore, the rotating speed of the runner, and the voltage generated by the electric generator are maintained to be nearly constant in spite of great variation of the sucking quantity. It follows a description of an embodiment of the invention with reference to the drawings, of which: Figure 1 is a cross sectional view illustrating a section including a turbine runner and an electric generator of an embodiment according to the present invention; Figure 2 is a cross sectional view of a main portion taken along a line II-II in Fig. 1; Figure 3 is a cross sectional view taken along a line III-III in Fig. 1; Figure 4 is a side view of a main portion in Fig. 1, illustrating a valve returning spring; Figure 5 is a schematic view illustrating an arrangement of a vacuum cleaner in its entirety; Figure 6 is a vertical cross sectional view illustrating an operating section of the vacuum cleaner, as an example; and Figure 7 is a chart illustrating relative characteristics of rotating speed/generated voltage to variation of degree of vacuum in case a butterfly valve is employed and in case the butterfly valve is not employed. Hereinafter, we explain the present invention in detail according to an embodiment. Figure 1 is a cross sectional view illustrating a section including a turbine runner and an electric generator of an embodiment according to the present invention. In Fig. 1, a turbine runner 24 is provided within a pipe body 23 which includes a sucking opening 21 and an opening for a sucking pipe. A rotary shaft 25 of the turbine runner 24 is directly coupled to a rotary shaft 27 of an electric generator 26. This arrangement and a point that the arrangement is housed in an operating section, are nearly the same as the arrangement and the point illustrated in Fig. 6. A characteristic point of this embodiment is that a butterfly valve 28 is provided between the turbine runner 24 in the pipe body 23 which constitutes a sucking path and the opening 22 for the pipe body 23. This butterfly valve 28 slightly has an oval plate shape when it is seen from the front side thereof, as is illustrated in Fig. 2. And, the butterfly valve 28 is maintained to be inclined by about 30 degrees (the condition illustrated in Fig. 1) by a valve returning spring 30 which is provided to a valve shaft 29. The butterfly valve 28 comprises an upper and a lower half valve plate 28a, 28b. In this embodiment, when sucking begins, the air flows from the sucking opening 21, through the pipe body 23, and towards the opening 22. The turbine runner 24 is rotated by a force of the air flow, and the electric generator 26 is respondingly rotated so as to generate a voltage. When a quantity of the air flow is small, the butterfly valve 28 is inclined slightly from the vertical attitude. But, when the quantity of the air flow increases, a rotating force in a direction illustrated by an arrow is generated in the upper half wing (upper half valve plate) 28a of the butterfly valve 28 so that the butterfly valve 28 moves to close the horizontal attitude from the inclined attitude. The valve (28) also comprises a lower half valve plate 28b. Consequently, an effective opening area of the opening 22 decreases, an increase of the quantity of the air flow is disturbed. And, an increase of the rotating speed of the turbine runner 24 is disturbed to some degree. Also, an increase of the voltage generated by the electric generator 26 is disturbed to some degree. When the degree of vacuum further increases, and the quantity of the air which is going to flow in the opening 22 develops a tendency to increase remarkably, the butterfly valve 28 receives a great air pressure. Therefore, the air pressure overcomes the force of the valve returning spring 30, and the butterfly valve 28 further rotates in the direction illustrated by the arrow. The butterfly valve 28 stops its rotation in a condition that the butterfly valve is just a nearly horizontal attitude because the air pressures acting to the butterfly valve 28 and the force of the valve returning spring 30 are balanced in such condition. In this condition, the opening 22 becomes nearly closed condition in almost portion of the effective area thereof so that the increase of the air passing through the opening 22 is remarkably limited and suppressed. Consequently, the increase of the rotating speed of the turbine runner 24 is remarably suppressed. The risining of the voltage generated by the electric generator 26 is remarkably suppressed as natural results. Therefore, making the generated voltage to an almost constant voltage is performed, which achieves the initial object. Relative characteristics of rotating speed/generated voltage to variation of vacuum pressure in case the butterfly valve 28 is employed (refer to curve A in Fig. 7) and in case the butterfly valve 28 is not employed (refer to curve B in Fig. 7), are illustrated in Fig. 7. A rather almost constant generated voltage is obtained in the case that the butterfly valve 28 is employed.

Claims: A vacuum cleaner which comprises a suction hose section (2, 9, 10), a runner (24) which rotates responding to a sucking force, and an electric generator (26) which is rotated by a rotating force of said runner (24) so as to generate a voltage, characterized by a body (23) having a sucking opening (21) and an opening (22) connected to said suction hose section (2, 9, 10), the body (23) housing said runner (24), and a passing through quantity controlling valve (28) which is provided between said runner (24) and said opening (22) in a passing path for said runner and adjusts a passing through quantity responding to an outside air sucking pressure. A vacuum cleaner as set forth in claim 1, characterized in that said passing through quantity controlling valve (28) is a ventilating quantity controlling valve, and said ventilating quantity controlling valve (28) is provided in a ventilating path of said runner (24). A vacuum cleaner as set forth in claim 1 or 2, characterized in that said valve (28) includes a rotary shaft (29) and a pair of valve plates (28a, 28b) which are disposed on opposite sides of said rotary shaft (29). A vacuum cleaner as set forth in claim 3, characterized in that said rotary shaft (29) inlcudes a valve returning spring (30) which regulates rotating of said ventilating quantity controlling valve (28), the rotating being caused by sucked outside air.

Inventors: ISHIKAWA MASAHIRO, ISHIKAWA, MASAHIRO, ISHIKAWA, MASAHIRO, C/O YASHIMA ELECTRIC CO., LTD.
Applicants: YASHIMA DENKI KK, YASHIMA ELECTRIC CO., LTD. OF ISHIHARA NOGAMI
Application year: 1994
Main classification: A47L9
IPC codes: A47L9